09-08-2009, 09:55 PM
I replaced the speaker on a 42-380 with a 15" modern replacement 8 ohm speaker. I bought a 10H choke from Radio Daze and added a series resistance to make the total resistance qpprox. equal to the original field coil resistance. I mounted the choke and resistors (2 X RW67V 5W) on the speaker as the resistors only dissipated about 4W.
You could also mount the choke and resistors in the chassis if there is room. Be sure to use a universal speaker replacement that has an efficiency at least 92 db/w or there will not be enough power to drive it properly. Many modern speakers such as those available from Parts Express are made for extended fidelity and the compromise is lower efficiency. Email me and I can send you more info and a circuit diagram.
Steve D
You could also mount the choke and resistors in the chassis if there is room. Be sure to use a universal speaker replacement that has an efficiency at least 92 db/w or there will not be enough power to drive it properly. Many modern speakers such as those available from Parts Express are made for extended fidelity and the compromise is lower efficiency. Email me and I can send you more info and a circuit diagram.
Steve D
